STUDIES ON ANTIOXIDANTS .1. PHENOLIC ANTIOXIDANTS AS STABILIZERS FOR POLYPROPYLENE

A group of phenolic antioxidants was synthesized, characterized and th e performance of these antioxidants in polymer processing was tested i n the polymer melt by multiple extrusions. The change in melt flow was observed and compared with the change in melt flow by use of commerci ally available antioxidants. All the antioxidants examined had the sam e phenolic stabilization moiety but varied in the size of the substitu ents in the pam-position of the aromatic ring. Increasing length of th e side chain considerably influences the behaviour of the antioxidants in the polymer and thus their effectiveness.